This proposal seek to extend the knowledge already accumulated about recombinant adenoviral gene transfer to the pancreas, and to use this knowledge to study two fundamental problems of pancreatic biology-pancreatic regeneration and islet morphogenesis. The experiments outlined below were planned based on four overarching hypotheses which have been developed based on the preliminary work done in the laboratory of the PI, as well as extensive review of the literature: 1.) The transient gene expression seen in pancreatic cells transduced with recombinant adenoviruses can be overcome by further study of the mechanisms involved; 2.) Host immunomodulation is one promising strategy for establishing long-term gene expression; 3.) Recombinant adenoviruses can be engineered to express genes involved in pancreatic growth and used as probes to elucidate the biology of regeneration; 4.) Recombinant adenoviruses will be useful in designing innovative strategies to study islet morphogenesis, and ultimately target the islets for gene therapy in vivo. The following Specific Aims will be undertaken in the conduct of this grant: 1.) To study the interaction of recombinant adenoviral vectors with the pancreas of immunocompetent/immunodeficient mice; 2.) To study the interaction of recombinant adenoviral vectors with the pancreas of immunodeficient mice, and to test innovative approaches to prolonging viral transgene expression in pancreata transduced into immunocompetent mice; 3.) To study the effect of physiologic perturbations (streptozotocin, acute pancreatitis, pancreatic resection) on stability of pancreas directed gene transfer; 4.) To study the effect of recombinant adenoviruses encoding the pancreatic growth genes regA and regB as well as hepatocyte growth factor (HGF) in attempts to stimulate pancreatic regeneration; 5.) To target beta cells of the islets of Langerhans by promoting long-tern gene expression and observing transit of transgene expressing cells from the periphery. The information learned from these studies will be important in understanding the biology of pancreatic regeneration and islet morphogenesis. The work will also allow a deeper understanding of pancreatic immunology and the development of innovative strategies for pancreas and islet-directed gene therapy.